Estimate the monthly payment, total interest, and repayment cost for a fixed-rate installment loan.
The calculator keeps the balance, rate convention, payment timing, fees, and term visible so you can reproduce the result and compare it with an actual offer or statement.
The cash-flow relationship
Place every amount at the correct time
Payment = P·r/(1−(1+r)^−n), where r is the entered nominal annual rate divided by 12; at a zero rate, payment = P/n.
Visual explanation
What changes the borrowing result
Opening balance
interestprincipal
Monthly paymentClosing balance falls over timePayment = P·r/(1−(1+r)^−n), where r is the entered nominal annual rate divided by 12; at a zero rate, payment = P/n.
Read the result in context
Use the estimate with its contract assumptions
A 20,000 loan at 6% for 60 months has a monthly payment of about 386.66.
The model assumes equal end-of-month payments and a constant entered rate. Fees, insurance, taxes, payment holidays, and penalties are excluded.
Quick guide
How to use this calculator
Enter every amount in one consistent currency.
Use the nominal annual rate and whole-number monthly timing requested by each label.
Read the result together with the stated timing convention and calculator-specific exclusions.
Calculation method
Calculation method
Payment = P·r/(1−(1+r)^−n), where r is the entered nominal annual rate divided by 12; at a zero rate, payment = P/n.
Entered monetary components are aggregated as exact fixed decimals. Amortization keeps full calculation precision and rounds only for presentation; a nonzero supported result is never displayed as zero.
Worked example
Worked example
A 20,000 loan at 6% for 60 months has a monthly payment of about 386.66.
Payment = P·r/(1−(1+r)^−n), where r is the entered nominal annual rate divided by 12; at a zero rate, payment = P/n.
Supported inputs
Precision and limits
Visible input limits
Amounts are capped at 1e12, nominal annual rates at 1000%, schedules at 1,200 months, and fixed-decimal inputs at 12 decimal places.
Estimate, not an offer
Results model only the entered values. A lender or contract may use different payment dates, day counts, compounding, fee treatment, statement rounding, or allocation rules.
International scope
No currency, country, tax, credit-scoring system, consumer-credit law, or lender policy is assumed. Location-dependent amounts must be entered explicitly.
Calculator-specific assumptions
The model assumes equal end-of-month payments and a constant entered rate. Fees, insurance, taxes, payment holidays, and penalties are excluded.
